Series RM Rate-Master® Polycarbonate Flowmeter

2", 5" or 10" Scale, Interchangeable Bodies

The SERIES RM Rate-Master® Flowmeters are a line of general use, direct reading
precision flowmeters suitable for both gas and liquid applications. This Series consists
of 2" (51 mm), 5" (127 mm) and 10" (254 mm) scales that can be panel or surface
mounted with optional precision metering valves. Within a given Series, the Rate-
Master® flowmeter bodies can be instantly interchanged, allowing the piping to remain
undisturbed, interchangeability of the ranges, and easy cleaning.

DID YOU KNOW that you can add YOUR logo to our Rate-Master® Flowmeter, call customer service for details.

Dwyer® Rate-Master® flowmeters are designed to provide satisfactory
long term service when used with air, water, or other compatible media.
Refer to factory for information on questionable gases or liquids. Caustic
solutions, anti-freeze (ethylene glycol) and aromatic solvents should
definitely not be used.

.05-.5 SCFH Air
.1-1 SCFH Air
.2-2 SCFH Air
.5-5 SCFH Air
1-10 SCFH Air
2-20 SCFH Air
5-50 SCFH Air
10-100 SCFH Air
15-150 SCFH Air
20-200 SCFH Air
5-50 cc/min Air
10-100 cc/min Air
30-240 cc/min Air
50-500 cc/min Air
100-1000 cc/min Air
200-2500 cc/min Air
400-5000 cc/min Air
1000-10000 cc/min Air
.5-5 LPM Air
1-10 LPM Air
2- 25 LPM Air
5-50 LPM Air
5-70 LPM Air
10-100 LPM Air
5-50 cc/min Water
10-110 cc/min Water
20-300 cc/min Water
1-11 GPH Water
2-24 GPH Water
4-34 GPH Water
5-50 GPH Water

5-50 SCFH Air
10-100 SCFH Air
20-200 SCFH Air
40-400 SCFH Air
60-600 SCFH Air
100-1000 SCFH Air
120-1200 SCFH Air
200-1800 SCFH Air
1-10 SCFM Air
2-20 SCFM Air
3-30 SCFM Air
2-20 GPH Water
8-90 GPH Water
.1-1 GPM Water
.2-2.2 GPM Water
.4-4 GPM Water
.8-7 GPM Water
1.2-10 GPM Water

Questions

I am looking to use an "Air" flowmeter RMA-6-SSV to monitor CO2 flow. I am wondering if there are are any concerns or correction factors I need to apply.

Answer

A specific gravity correction factor will need to be considered when monitoring other gases with a meter calibrated for air. The correction factor equation is as follows:
Q2=Q1 x sqrt (1/S.G.)
Where: Q1= Observed Flowmeter reading
Q2= Standard Flow Corrected for Specific Gravity
1= Specific Gravity of Air or Water
S.G.= Specific Gravity of media being used in flowmeter originally calibrated for air or water.
This equation can be found in the beginning of the Flow section in the catalog. Alternatively, special ranges and scales can be provided; for specific information please contact our customer service department.
For further information, see our "Tech & Specs" Video Blog: Fix your Flow... Specific Gravity and Pressure Corrections for Variable Area Flowmeters (Episode 4), in Dwyer's Video Library.

The older version of the RMC used to have a pressure limit of 35psi because the backplate was assembled from 2 seperate pieces. The pressure rating increased to 100psi when we began to stamp the backplate from 1 solid piece.

For the VFA-44-BV product, what is the minimum flow that I can reliably control with a pressure head of up to 4 bar? Will the needle valve function properly at that pressure/flow combination? Thank you.

Answer

At a pressure of 4 bar (58 psi), the needle valve should function properly and provide reliable control over the whole range, which is 8-40 gallons of water per hour.

Is the Rate-Master® or Visi-Float® Flowmeter compatible with any media?

Answer

The Rate-Master® Flowmeter is manufactured from a polycarbonate plastic and the Visi-Float® Flowmeter is manufactured from acrylic. Compatibility charts need to be reviewed to determine if these materials of construction are compatible with your media.

Why are top mounted valves recommended for flowmeters used for vacuum service?

Answer

To maintain atmospheric pressure in the indicating bore and therefore preserve accuracy; an inlet restriction would reduce pressure in the bore. This is essentially the opposite situation to outlet back-pressure in a pressure system which increases pressure in the bore and also affects accuracy. Remember that all standard Dwyer flowmeters are calibrated for standard atmospheric pressure and temperature in the bore.

What factor is used to correct for different flowmeter inlet pressure?

Answer

If the flowmeter is exhausting to atmosphere, no correction factor is needed. If back-pressure is present due to downstream plumbing or restrictions, this error can be corrected utilizing the conversion curves in our full-line catalog or the following equation.